diff --git a/configure.ac b/configure.ac
index 07abd4d4..0622a5c9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -392,7 +392,6 @@ AM_CFLAGS="$AM_CFLAGS -Wimplicit-function-declaration"
 AM_CFLAGS="$AM_CFLAGS -Wundef"
 AM_CFLAGS="$AM_CFLAGS -Wfloat-equal -Wredundant-decls"
 AM_CFLAGS="$AM_CFLAGS -fstack-protector-strong -fno-common"
-AM_CFLAGS="$AM_CFLAGS -D_FORTIFY_SOURCE=2"
 AM_CFLAGS="$AM_CFLAGS -std=gnu99 -ggdb3"
 
 # GCC-specific warnings (not supported by clang) — test each one